Purge system for blow-by return valve



J. H. MACPHERSON, JR, ETAL 3,105,471

PURGE SYSTEM FOR BLOW-BY RETURN 2 Sheets-Sheet 1 Oct. 1, 1963 Filed June1, 1982 llllm oyo lllll llll Ill INVENTORS JOHN HUGH MACPHERSOMJR. JAMESO. CLAYTON ATTORNEY Oct. 1, 1963 J. H. MACPHERSON, JR, ETAL 3,

PURGE SYSTEM FOR BLOW-BY RETURN VALVE Filed June 1, 1962 2 Sheets-Sheet2 l N V E NT 0 R 5 JOHN HUGH MA CPI-IERSON, JR. JAMES 0. CLAYTON UnitedStates Patent 3,105,471 PURGE SYSTEM FOR BLOW-BY RETURN VALVE John HughMacpherson, Jr., and James 0. Clayton,

Berkeley, Calif., assignors to California Research Corporation, SanFrancisco, Calif., a corporation of Bela- Ware Filed June 1, 1962, 881'.No. 199,374 3 Claims. (Cl. 123119) The present invention relates toblow-by return systems for internal combustion engines. Moreparticularly, it relates to apparatus for maintaining in an operatingcondition the reciprocating elements of a vacuum control valve in ablow-by return line connecting a crankcase breather pipe to the fuel-airintake system of an internal combustion engine.

It has been known heretofore that smog and other noxious fumes createdby internal combustion engines using a splash-type lubrication systemcan be reduced by connecting the crankcase breather pipe to the intakesystem, such as the intake manifold or carburetor, of the engine.Because of the widely varying pressure conditions in both the crankcaseand in the carburetor, it has been common to connect these unitstogether through a crankcase recirculation control valve. The functionof this valve is to prevent abnormally high vacuums, normally producedin a carburetor during acceleration or highspeed operation, fromimposing a vacuum on the crankcase which might pull oil, as well asfumes, from the crankcase. It has been found in practice, however, thatsuch blow-by return line valves are easily clogged with carbon deposits,such as oil vapors condensing thereon. As a result, thepressure-difierential, spring-operated recip rocating throttling elementin the line becomes lodged (stuck) in one position. This position is onewhere the valve is normally closed so that no gases are in fact returnedto the carburetor. Due to this blocking of the control valve in theblow-by return line, the return of the vapors (fumes) from the crankcasebreather to the intake system of the engine is rendered impossible. Thefumes then escape under the engine hood and thence pass into the outsideatmosphere, contributing to air pollution (smog), and also penetrateinto the passenger compartment, causing irritation and discomfort to thedriver and passengers.

*It is a particular object of the present invention to provide a systemfor assuring continued operation of the crankcase recirculation controlvalve in a blow-by return line, which connects the crankcase breatherpipe to the intake of an internal-combustion, spark-ignition engine, bysupplying, at least intermittently, and independently of the flow rateof vapors in the blow-by return line, a small but effective quantity ofliquid gasoline from the engine supply to the return line ahead of thevalve so that said valve is washed to remove deposits of oil and carbon,which would otherwise clog the moving elements of the valve.

In a preferred form of apparatus for carrying out the invention, a jetnozzle, shaped in the fashion of a Pitot tube, is directly connected tothe engine fuel supply and enters the blow-by return line ahead of therecirculation control valve so that a small but effective amount offresh, uncontaminated liquid gasoline can be sprayed directly on all ofthe reciprocating elements of the valve. These 3,105,471 ?atented Oct.1, 1963 elements consists of a piston-like throttling member thatreciproca-tes in line with the flow of vapors and a spring to hold thethrottling element in a normally closed posi tion. Fresh liquid gasolineis sprayed on these elements by a jet located in the blow-by return linedirectly ahead of the valve. Gasoline is supplied to this jet each timethe accelerator jets are actuated on the carburetor proper. Since theaccelerator jets operate only intermittently, the volume of gasolinewill also be small. Additionally, this supply of gasoline is independentof the pressure difierential applied to the blow-by return line. Inoperation, such washing will thus occur oftener in start-and-stopdriving than under continuous, high-speed driving conditions. Since suchintermittent driving tends to deposit materials on the reciprocatingelements, washing action is most needed under these conditions.

Desirably, but not necessarily, the fuel should contain dispersed ordissolved therein a detergent additive in sufficient quantity todissolve varnish, lacquer, carbon, and other oil-vapor deposits that maybuild up on prolonged operation of the blow-by return system athigh-load conditions. Such high-load blow-by conditions exist indelivery trucks and taxicabs where prolonged periods of idling operationpermit vapors to build up without high-cooling air flow over and throughthe engine compartment.

Further objects and advantages of the present invention will becomeapparent from the following detailed description, taken in conjunctionwith the accompanying drawings which form an integral part of thepresent specification.

In the drawings:

FIG. 1 is a schematic view of an automobile engine to which the presentinvention has been applied; the engine is shown partially in crosssection to explain the purpose and function of the present invention inpreventing breather-pipe fumes from clogging the crankcase recirculationvalve in the blow-by return line to the carburetor.

FIG. 2 is an enlarged cross-sectional elevation View through thecirculation control valve and a part of the throttle body of thecarburetor mounted on the engine, as shown in FIG. 1.

FIG. 3 is an end elevation View through the control valve seen in FIG.2, and taken in the direction of arrow 33.

Referring now to the drawings, and in particular to FIG. 1, there isillustrated a typical automobile engine 16 to which the presentinvention has been applied. For a clearer understandng of the purposeand reason for the present invention, it is necessary at this point todisgress slightly and explain how blow-by is produced in a typicalinternal combustion engine. The term blow-by as used in the art is meantto include any fumes or gases that are created in the crankcase, or oilsump, 11 wherein lubricating oil, introduced into the engine throughfiller pipe 12 is contained in sufficient volume, so that rotation ofthe crankshaft, not shown, and connecting rods, such as 13, connected topiston 14, lubricates the engine by splashing the oil. Since thetemperature of the lubricating oil varies with the temperature of theengine, it is necessary to provide air vents for the crankcase. For thispurpose, filler pipe cap 15 on filling tube 12 has air passages formedtherein, and in this Way, as indicated by the arrows, air enters thecnankcase through filler tube 12. At the same time, the crankcase isalso provided with a breather tube located below the pistons, but abovenormal oil level in crankcase 11. This is indicated by 16 in FIG. 1,and, as shown in phantom at 17, the breather tube normally is open andturned down so that fumes exhaust beneath the automobile and in thevicinity of the engine exhaust pipe. 7

It has been known for a long time that fumes coming from a breathertube, such as 17, can create smog and other noxious fumes in theatmosphere. The varying temperature of the oil creates such fumes, but amore serious source of fumes from the crankcase is both burned andunburned gases generated in combustion chambers 18. Upon slight Wear ofthe cylinder walls 19, these combustion gases pass between walls 19 andpiston rings 26. Flow of these gases is also indicated by arrows. It isparticularly these gases, which are truly and correctly termed blow-by,"that constitute one of the major sources of smog when they are permittedto exit directly to the atmosphere as through a breather pipe 17.

With the foregoing explanation in mind, it will be unde stood why it hasbeen proposed heretofore that a breatherpipe return line 22 be used forpiping such gases back into the intake of the automobile. Normally, sucha line may be introduced to any part of the intake system, but in thepresent arrangement, and in accordance with a preferred form of thisinvention, return line 22 is connected to the engine intake through aspacer plate 24 that is easily and readily installed merely by removingcarburetor 26 from its mounting on the intake manifold mounting block27.

It will be readily understood by those skilled in the art that thepressures both in crankcase 11 and in throttle body 26 will varyconsiderably during operation of the automobile. For example, when anautomobile is decelerating, the negative pressure, or vacuum, inthrottle body 23 will sharply increase due to suction created by pistons14 on their intake strokes, and the closing of the throttle blade byrelease of accelerator pedal 29 (FIG. 1). At the same time, the pressurein the crankcase may be positive due to excessive blow-by past thepistons and piston rings of the engine. Under these circumstances, thepressure difierential across blow-by return line 22 may be excessive,and Would normally cause oil being splashed about in the crankcase to bedrawn into line 22. For this purpose, there has been proposed use of abackpressure control valve 30. Construction of valve 34) is shown ingreater detail in FIGS. 2 and 3. As indicated above, however, cloggingof this valve has been frequent, and when it becomes clogged the blow-byreturn line is inoperative.

'For the foregoing reasons, and in accordance with the presentinvention, there is provided apparatus for injecting a small, buteffective, amount of uncontaminated, fresh liquid gasoline into blow-byreturn line 22 upstream from valve 30 so that all of the reciprocatingelements of the valve rare at least intermittently washed with a smallamount of the engine-operating gasoline. For this purpose, asillustrated in FIGS. 1 and 2, conduit 32 is connected between carburetor26 and blow-by return line 22. As best seen in FIG. 2, tube '32 ends ina Pitot, or jet, tube arrangement identified as 34, so that liquid canbe sprayed directly onto the throttling element 36, spring 49, and thevalve seats of valve 30.' While not shown in detail, pipe 32 is directlyconnected to the fuel accelerator jets of carburetor 26. These jets areoperated intermittently by the linkage indicated generally as cam 38 androd 39 in carburetor 26, as shown in FIG. 1. As is understood in theconstruction of carburetors, when foot feed, or accelerator, 29 isdepressed sharply against the action of spring 40, linkage rod 41 notonly opens the throttle blade 25 (FIG. 2) in the throttle body 28, butalso actuates the accelerator jets through cam linkage 38 and rod 39.This action sends a metered amount of fresh fuel to the carburetor. Bythe present arrangement, at least a part of this fuel in liquid form,and before it is mixed with air, is supplied to conduit 32. By sodirecting part of the accelerator jet fuel supply, it is possible notonly to supply the needed burst of fuel to the engine, but at the sametime to wash throttle element 36, spring 49, and the valve seats ofvalve 30. V

For a full understanding of Why the present invention is needed toprevent blocking of the blow-by return line, reference is now made tothe detailed construction of the back-pressure control valve 30, as bestseen in FIGS. 2 and 3. As there indicated, body 43 of valve 30 includesthree axially aligned bores identified as 44, 45, and 46. It will benoted that bore 44 is smaller than 45, and in turn bore 4-5 is smallerthan 4-6. The bottom of bores 45 and 46, respectively, forms shouldersor seats 47 and 48 against which movable element 36 may seat and unseatby action of the pressure differential between bores 44 and 46 andspring 4-9.

It will be further noted that movable element 36 includes four Wingsegments 50 that seat on shoulder 48 and in turn form a seat for one endof spring 49. When seated, as shown in FIG. 2, gas flows through element36 by way of the spaces formed between wing sections 56 and transversebore 52 and needle 54 in tapered end 55 of element 36. In the positionof FIG. 2, valve element 36 seats against shoulder 47 by the combinedforce of vacuum in throttle body 28, due to the closing of throttleplate 25, and the pressure differential between line 22 and throttlebody 28. When the intake manifold vacuum is reduced, valve element 36moves toward the right by the action of spring 49. In its extremeposition, wing sections 5% can rest against the end of fitting 60.

Other obvious arrangements to supply fresh liquid gasoline to washintermittently the reciprocating elements of the control valve in theblow-by return line include a pump electrically actuated by the ignitionkey or mechanical ly actuated by application of the emergency brake.Other electrical, hydraulic, or mechanical means may be effectively usedto spray gasoline onto the valve in the blow-by return line between thecrankcase and the fuel-air intake system of the engine to forestallblockin g of the control valve.

\As mentioned before, it may be found desirable to use an engine fuelwhich contains an effective amount of detergent or solvent material whenusing the apparatus of the present invention. Such an additive willassure continued operation even under heavy blow-by conditions, such asprolonged idling of the engine while hot.

While various modifications and changes in our apparatus to preventblocking of the movable elements in a crankcase recirculation controlvalve in a blow-by return line will occur to those skilled in the art,all such modifications and changes comprehended by the claims areintended to be included therein.

This application is a continuation in part of our application Serial No.67,639, filed November 7, 1960 and now abandoned.

We claim:

1. Apparatus for assuring continued operation of a pressure-responsivecheck valve all of whose reciprocating elements are directly in the flowpath of a blow-by return line that connects a crankcase breather pipe tothe intake system of an internal-combustion spark-ignition engine whichcomprises means for spraying liquid gasoline directly on saidreciprocating elements :of said control valve, said spray meansincluding a spray jet in said return line and conduit means connectingsaid spray jet to a supply of liquid gasoline, and means for at leastintermittently injecting liquid gasoline into said conduit, saidinjecting means being operative independently of the vapor flow ratethrough said return line whereby said reciprocating elements of saidvalve are washed to remove oil and carbon deposits therefrom that wouldinactivate said check valve.

2. Apparatus for washing the reciprocating elements of a flow-responsivecheck valve with liquid gasoline to keep said valve operating in ablow-by return line that connects a crankcase breather pipe to theintake system of an internal-combustion spark-ignition engine whichcomprises means for injecting liquid gasoline directly into said returnline at a position to spray directly onto said reciprocating elements ofsaid control valve, said injecting means including a spray jet in saidreturn line and conduit means connecting said spray jet to a supply ofliquid gasoline, and means for at least intermittently applying pressureto liquid gasoline in said conduit to spray said gasoline independentlyof the flow rate of vapors in said return line whereby saidreciprocating parts of said valve are washed to remove oil and carbondeposits therefrom that would inactivate said control valve.

3. Apparatus in accordance with claim 2 in which said pressure-applyingmeans is operative with the accelerator jets of the carburetor for saidspark-ignition engine.

References Cited in the file of this patent UNITED STATES PATENTS2,080,588 Whittington May 18, 1937

1. APARATUS FOR ASSURING CONTINUED OPERATION OF A PRESSURE-RESPONSIVECHECK VALVE ALL OF WHOSE RECIPROCATING ELEMENTS ARE DIRECTLY IN THE FLOWPATH OF A BLOW-BY RETURN LINE THAT CONNECTS A CRANKCASE BREATHER PIPE TOTHE INTAKE SYSTEM OF AN INTERNAL-COMBUSTION SPARK-IGNITION ENGINE WHICHCOMPRISES MEANS FOR SPRAYING LIQUID GASOLINE DIRECTLY ON SAIDRECIPROCATING ELEMENTS OF SAID CONTROL VALVE, SAID SPRAY MEANS INCLUDINGA SPRAY JET IN SAID RETURN LINE AND CONDUIT MEANS CONNECTING SAID SPARYJET TO A SUPPLY OF LIQUID GASOLINE, AND MEANS FOR AT LEASTINTERMITTENTLY INJECTING LIQUID GASOLINE INTO SAID CONDUIT, SAIDINJECTING MEANS BEING OPERATIVE INDEPENDENTLY OF THE VAPOR FLOW RATETHROUGH SAID RETURN LINE WHEREBY SAID RECIPROCATING ELEMENTS OF SAIDVALVE ARE WASHED TO REMOVE OIL AND CARBON DEPOSITS THEREFROM THAT WOULDINACTIVATE SAID CHECK VALVE.